Evans S Lagudah

The Commonwealth Scientific and Industrial Research Organisation | CSIRO · Division of Plant Industry

Partial resistance to multiple biotrophic fungal pathogens in wheat (Triticum aestivum L.) is conferred by a variant of the Lr67 gene, which encodes a hexose-proton symporter. Two mutations (G144R, V387L) differentiate the resistant and susceptible protein variants (Lr67res and Lr67sus). Lr67res lacks sugar transport capability and was associated w...

Bread wheat ( Triticum aestivum ) is a globally dominant crop and major source of calories and proteins for the human diet. Compared to its wild ancestors, modern bread wheat shows lower genetic diversity caused by polyploidisation, domestication, and breeding bottlenecks. Wild wheat relatives represent genetic reservoirs, harbouring diversity and...

Most rust resistance genes thus far isolated from wheat have a very limited number of functional alleles. Here, we report the isolation of most of the alleles at wheat stem rust resistance gene locus SR9. The seven previously reported resistance alleles (Sr9a, Sr9b, Sr9d, Sr9e, Sr9f, Sr9g, and Sr9h) are characterised using a synergistic strategy. L...

Leaf rust, caused by Puccinia hordei, is one of the most widespread and damaging foliar diseases affecting barley. The barley leaf rust resistance locus Rph7 has been shown to have unusually high sequence and haplotype divergence. In this study, we isolate the Rph7 gene using a fine mapping and RNA-Seq approach that is confirmed by mutational analy...

Many disease resistance genes in wheat (Triticum aestivum L.) confer strong resistance to specific pathogen races or strains, and only a small number of genes confer multipathogen resistance. The Leaf rust resistance 67 (Lr67) gene fits into the latter category as it confers partial resistance to multiple biotrophic fungal pathogens in wheat and en...

Leaf rust, caused by Puccinia hordei , is one of the most widespread and damaging foliar diseases affecting barley ( Hordeum spp.). The barley leaf rust resistance locus Rph7 , located on the short arm of chromosome 3H, confers defence at all growth stages and was previously shown to have unusually high sequence and haplotype divergence. Earlier, f...

Most resistance genes thus far isolated from wheat have a very limited number of functional alleles, with the exception of the powdery mildew PM3 resistance locus. Here we report the isolation of most of the alleles at wheat stem rust resistance gene locus SR9 , representing the largest multi-allelic rust resistance locus in common wheat. The seven...

Key message Stripe rust resistance gene YrAet672 from Aegilopstauschii accession CPI110672 encodes a nucleotide-binding and leucine-rich repeat domain containing protein similar to YrAS2388 and both these members were haplotypes of Yr28. Abstract New sources of host resistance are required to counter the continued emergence of new pathotypes of th...

Developing wheat varieties with durable resistance is a core objective of the International Maize and Wheat Improvement Center (CIMMYT) and many other breeding programs worldwide. The CIMMYT advanced wheat line “Mucuy” displayed high levels of resistance to stripe rust (YR) and leaf rust (LR) in field evaluations in Mexico and several other countri...

Key message Stem rust resistance genes, SrRL5271 and Sr672.1 as well as SrCPI110651, from Aegilops tauschii, the diploid D genome progenitor of wheat, are sequence variants of Sr46 differing by 1–2 nucleotides leading to non-synonymous amino acid substitutions. Abstract The Aegilops tauschii (wheat D-genome progenitor) accessions RL 5271 and CPI11...

Wheat plants are infected by diverse pathogens of economic significance. They include biotrophic pathogens like mildews and rusts that require living plant cells to proliferate. By contrast necrotrophic pathogens that cause diseases such as tan spot, Septoria nodurum blotch and spot blotch require dead or dying cells to acquire nutrients. Pioneerin...

Leaf rust and stripe rust are important wheat diseases worldwide causing significant losses where susceptible varieties are grown. Resistant cultivars offer long-term control and reduce the use of hazardous chemicals, which can be detrimental to both human health and the environment. Land races have been a valuable resource for mining new genes for...

Partial resistance to multiple biotrophic fungal pathogens in wheat (Triticum aestivum L.) is conferred by the Lr67 gene, which encodes a Sugar Transport Protein 13 (STP13) family hexose-proton symporter variant. Two mutations (G144R, V387L) differentiate the resistant and susceptible protein variants (Lr67res and Lr67sus). The molecular function o...

Aegilops tauschii, the diploid wild progenitor of the D subgenome of bread wheat, is a reservoir of genetic diversity for improving bread wheat performance and environmental resilience. Here we sequenced 242 Ae. tauschii accessions and compared them to the wheat D subgenome to characterize genomic diversity. We found that a rare lineage of Ae. taus...

Key message Adult plant stem rust resistance locus, QSrGH.cs-2AL, was identified in durum wheat Glossy Huguenot and mendelised as Sr63. Markers closely linked with Sr63 were developed. Abstract An F3 population from a Glossy Huguenot (GH)/Bansi cross used in a previous Australian study was advanced to F6 for molecular mapping of adult plant stem r...

An F 3 population from a Glossy Huguenot (GH)/Bansi cross used in a previous Australian study was advanced to F 6 for molecular mapping of adult plant stem rust resistance. Maturity differences among F 6 lines confounded assessments of stem rust response. GH was crossed with a stem rust susceptible F 6 recombinant inbred line (RIL), GHB14 (M14), wi...

Central to the diversity of wheat products was the origin of hexaploid bread wheat, which added the D-genome of Aegilops tauschii to tetraploid wheat giving rise to superior dough properties in leavened breads. The polyploidization, however, imposed a genetic bottleneck, with only limited diversity introduced in the wheat D-subgenome. To understand...

Leaf rust (LR) and stripe rust (YR) are important diseases in wheat producing areas worldwide and cause severe yield losses under favorable environmental conditions when susceptible varieties are grown. We determined the genetic basis of resistance to LR and YR in variety Borlaug 100 by developing and phenotyping a population of 198 F6 recombinant...

The re-emergence of stem rust on wheat in Europe and Africa is reinforcing the ongoing need for durable resistance gene deployment. Here, we isolate from wheat, Sr26 and Sr61, with both genes independently introduced as alien chromosome introgressions from tall wheat grass (Thinopyrum ponticum). Mutational genomics and targeted exome capture identi...

Resistance breeding is an effective approach against wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt). The synthetic hexaploid wheat line Largo (pedigree: durum wheat ‘Langdon’ × Aegilops tauschii PI 268210) was found to have resistance to a broad spectrum of Pgt races including the Ug99 race group. To identify the stem rust resista...

Breeding wheat with durable resistance to the fungal pathogen Puccinia graminis f. sp. tritici (Pgt), a major threat to cereal production, is challenging due to the rapid evolution of pathogen virulence. Increased durability and broad-spectrum resistance can be achieved by introducing more than one resistance gene, but combining numerous unlinked g...

Leaf rust, caused by Puccinia hordei is a devastating fungal disease affecting barley (Hordeum vulgare subsp. vulgare) production globally. Despite the effectiveness of genetic resistance, the deployment of single genes often compromises durability due to the emergence of virulent P. hordei races, prompting the search for new sources of resistance....

Aegilops tauschii, the diploid wild progenitor of the D-subgenome of bread wheat, constitutes a reservoir of genetic diversity for improving bread wheat performance and environmental resilience. To better define and understand this diversity, we sequenced 242 Ae. tauschii accessions and compared them to the wheat D-subgenome. We characterized a rar...

NBS-LRR-type disease resistance gene-like cDNA, induced by salicylic acid (SA) was cloned from rye Secalecereale L. (2n = 14RR) var. Petkus, which has rust resistance genes such as Lr26, Sr31 andRr9. We designed primers based on the NBS region and performed PCR using Petkus genomic DNA as a template. Next, we TA-cloned a 532-bp DNA fragment contain...

Pm1a, the first powdery mildew resistance gene described in wheat, is part of a complex resistance (R) gene cluster located in a distal region of chromosome 7AL that has suppressed genetic recombination. A nucleotide‐binding, leucine‐rich repeat (NLR) immune receptor gene was isolated using mutagenesis and R gene enrichment sequencing (MutRenSeq)....

In the last 20 years, stem rust caused by the fungus Puccinia graminis f. sp. tritici (Pgt), has reemerged as a major threat to wheat and barley production in Africa and Europe. In contrast to wheat with 82 designated stem rust (Sr) resistance genes, barley’s genetic variation for stem rust resistance is very narrow with only ten resistance genes g...

In the last 20 years, severe wheat stem rust outbreaks have been recorded in Africa, Europe, and Central Asia. This previously well controlled disease, caused by the fungus Puccinia graminis f. sp. tritici, has reemerged as a major threat to wheat cultivation. The stem rust (Sr) resistance gene Sr22 encodes a nucleotide-binding and leucine-rich rep...

Rust diseases continuously threaten global wheat production: stem rust, leaf rust, and yellow rust caused by Puccinia graminis f. sp. tritici, Puccinia triticina, and Puccinia striiformis f. sp. tritici, respectively. Recent studies indicated that the average losses from all these three rusts reached up to 15.04 million tons per year, which is equi...

Key message: Fine mapping of the barley leaf rust resistance locus Rph13 on chromosome 3HL facilitates its use in breeding programs through marker-assisted selection. Barley leaf rust (BLR-caused by Puccinia hordei) is a widespread fungal disease that can be effectively controlled by genetic resistance. There is an ongoing need to both diversify a...

NPR1 has been found to be a key transcriptional regulator in some plant defence responses. There are nine NPR1 homologues (TaNPR1) in wheat, but little research has been done to understand the function of those NPR1‐like genes in the wheat defence response against stem rust (Puccinia graminis f. sp. tritici) pathogens. We used bioinformatics and re...

The wheat-rust pathosystem has been well-studied among host–pathogen interactions since last century due to its economic importance. Intensified efforts toward cloning of wheat rust resistance genes commenced in the late 1990s with the first successful isolation published in 2003. Currently, a total of 24 genes have been cloned from wheat that prov...

Stem rust is an important disease of wheat that can be controlled using resistance genes. The gene SuSr-D1 identified in cultivar ‘Canthatch’ suppresses stem rust resistance. SuSr-D1 mutants are resistant to several races of stem rust that are virulent on wild-type plants. Here we identify SuSr-D1 by sequencing flow-sorted chromosomes, mutagenesis,...

Leaf rust, caused by Puccinia hordei is a devastating fungal disease affecting barley (Hordeum vulgare subsp. vulgare) production globally. Race-specific resistance (R) genes have been deployed widely; however, their durability is often compromised due to the rapid emergence of virulent P. hordei races, prompting the search for new sources of broad...

The International Maize and Wheat Improvement Center (CIMMYT)-derived durum wheat line Quetru is moderately resistant to leaf rust and displays disease severities of 15–30% at the adult plant stage. Atil C2000 is moderately susceptible to leaf rust at adult plant stage and displays severities of 20–60%. These two durum wheats were crossed with the...

Fhb1 is the most effective and most widely deployed source of durable resistance against Fusarium graminearum, a devastating toxin-producing fungal pathogen affecting wheat. Two new studies identify Fhb1 as an atypical disease resistance gene; this discovery is expected to fuel discussion on the molecular nature of this important disease-resistance...

The appearance of highly virulent and more aggressive races of Puccinia striiformis f. sp. tritici (Pst) during the last two decades has led to stripe rust epidemics worldwide and to the rapid erosion of effective resistance genes. In this study, we mapped an adult‐plant resistance locus from the Argentinean wheat (Triticum aestivum L.) cultivar Kl...

Key message We report transfer of a rust resistance gene named SrB, on the 6Ae#3 chromosome, to wheat by recombination with the 6Ae#1 segment carrying Sr26 and development of a linked marker. Abstract A stem rust resistance gene from a South African wheat W3757, temporarily named SrB, has been transferred onto chromosome 6A. Line W3757 is a 6Ae#3...

Disease resistance (R) genes from wild relatives could be used to engineer broad-spectrum resistance in domesticated crops. We combined association genetics with R gene enrichment sequencing (AgRenSeq) to exploit pan-genome variation in wild diploid wheat and rapidly clone four stem rust resistance genes. AgRenSeq enables R gene cloning in any crop...

Key message A set of molecular markers was developed for Sr26 from comparative genomic analysis. The comparative genomic approach also enabled the identification of a previously uncharacterised wheat chromosome that carried Sr26. Abstract Stem rust of wheat, a biotic stress caused by a fungal pathogen, continues to pose significant threats to whea...

Fungal pathogens are a major constraint to global crop production; hence, plant genes encoding pathogen resistance are important tools for combating disease. A few resistance genes identified to date provide partial, durable resistance to multiple pathogens and the wheat (Triticum aestivum) Lr67 hexose transporter variant (Lr67res) fits into this c...

Crop diseases reduce wheat yields by ~25% globally and thus pose a major threat to global food security1. Genetic resistance can reduce crop losses in the field and can be selected through the use of molecular markers. However, genetic resistance often breaks down following changes in pathogen virulence, as experienced with the wheat yellow (stripe...

In the last 20 years, stem rust caused by the fungus Puccinia graminis f. sp. tritici ( Pgt ), has re-emerged as a major threat to wheat and barley cultivation in Africa and Europe. In contrast to wheat with 82 designated stem rust ( Sr ) resistance genes, barley's genetic variation for stem rust resistance is very narrow with only seven resistance...

Crop diseases reduce wheat yields by ~25% globally and thus pose a major threat to global food security. Genetic resistance can reduce crop losses in the field and can be selected for through the use of molecular markers. However, genetic resistance often breaks down following changes in pathogen virulence, as experienced with the wheat yellow (str...

Growing resistant varieties is the most effective and economical method for controlling rust of wheat (Triticum aestivum L.). Resistance to leaf rust and stripe rust, caused by Puccinia triticina Erikss. and P. striiformis Westend. f. sp. tritici, respectively, was investigated in 148 F5 recombinant inbred lines derived from a cross between ‘Avocet...

The recently published reference genome of Aegilops tauschii provides new insights into the originator of the D genome donor of hexaploid wheat. This will be a foundation for exploring the genomic diversity underpinning adaptive traits in wheat, and ultimately advance wheat improvement efforts.

Genetic resistance is the most economic and environmentally sustainable approach for crop disease protection. Disease resistance (R) genes from wild relatives are a valuable resource for breeding resistant crops. However, introgression of R genes into crops is a lengthy process often associated with co-integration of deleterious linked genes 1, 2 a...

Key message: Thirteen potentially new leaf rust resistance loci were identified in a Vavilov wheat diversity panel. We demonstrated the potential of allele stacking to strengthen resistance against this important pathogen. Leaf rust (LR) caused by Puccinia triticina is an important disease of wheat (Triticum aestivum L.), and the deployment of gen...

Figure S1 Genomic blot of EcoRV‐restricted DNA from transgenic Sorghum. Figure S2 Lr34 sib and transgenic sorghum penultimate leaves. Figure S3 Rust sporulation on sorghum leaves 5 and 6 at 15 days post‐inoculation with P. purpurea. Figure S4 (a) Pustule development and (b) fungal biomass on transgenic sorghum leaves one month post‐inoculation w...

Recently, the Lr67 resistance gene was identified as a hexose transporter variant which confers adult plant rust and mildew resistance in wheat. Methodologies used to characterize the protein encoded by Lr67 may be of use to non-transporter experts conducting similar experiments with other hexose transporters. Hence, in this chapter, we detail a pr...

One of the most important tools to identify and validate rust resistance gene function is by producing loss-of-function mutants. Mutants can be produced using irradiation, chemicals, and insertions. Among all the mutagens, ethyl methanesulfonate (EMS) and sodium azide are most favored because of the ease of use and generation of random point mutati...

DNA is widely used in plant genetic and molecular biology studies. In this chapter, we describe how to extract DNA from wheat tissues. The tissue samples are ground to disrupt the cell wall. Then cetyltrimethylammonium bromide (CTAB) or sodium dodecyl sulfate (SDS) is used to disrupt the cell and nuclear membranes to release the DNA into solution....

Figure S1 Production of Lr34 transgenics in durum wheat cultivar Stewart. Figure S2 P. triticina infection phenotypes on durum wheat seedlings grown at 10 °C. Figure S3 DNA blot analysis of durum cultivar Stewart transgenic lines containing single‐copy insertions of the hexaploid wheat Lr34 gene. Figure S4 Replicate experimental quantification...

Table S1 Primers used for Q‐PCR and probe amplification.

The ability of the wheat Lr34 multi-pathogen resistance gene (Lr34res) to function across a wide taxonomic boundary was investigated in transgenic Sorghum bicolor. Increased resistance to sorghum rust and anthracnose disease symptoms following infection with the biotrophic pathogen Puccinia purpurea and the hemibiotroph Colletotrichum sublineolum r...

The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only appare...

Plants are energy storage factories. Photosynthetic cells convert energy from sunlight to sugars that are transported to growing tissues via both extracellular and intercellular trafficking pathways. Many pathogens have evolved mechanisms to infect the nutrient-rich niche of plant tissues and exploit these sugar pipelines. Some pathogens manipulate...

Background Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is a major wheat disease which is mainly controlled through the release of resistant cultivars containing one or several resistance genes. Considerable effort has been put into the discovery of new resistance genes, but knowledge of their mechanisms of action is often lacking....

Leaf rust (LR) and stripe rust (YR) are important diseases of wheat worldwide. We used 148 recombinant inbred lines (RIL) from the cross of Avocet × Kundan for determining and mapping the genetic basis of adult plant resistance (APR) loci. The population was phenotyped LR and YR for three seasons in field trials conducted in Mexico and genotyped wi...

Leaf rust (LR) caused by Puccinia triticina, is among the most important diseases of wheat (Triticum aestivum L.) crops globally. Deployment of cultivars incorporating genetic resistance, such as adult plant resistance (APR) or all-stage resistance, is considered the most sustainable control method. APR is preferred for durability because it places...

This study reports further characterization of the defence mechanism of an EMS-induced mutant (MNR220) that displays enhanced resistance to leaf rust, stem rust, stripe rust and powdery mildew diseases. The broad-spectrum resistance of the mutant was characterized by a microscopy study and additional race screenings of two rust pathogens. The mutan...

The hexaploid wheat (Triticum aestivum) adult plant resistance gene, Lr34/Yr18/Sr57/Pm38/Ltn1, provides broad spectrum resistance to wheat leaf rust (Lr34), stripe rust (Yr18), stem rust (Sr57) and powdery mildew (Pm38) pathogens, and has remained effective in wheat crops for many decades. The partial resistance provided by this gene is only appare...

Significance Stem rust caused by the fungus Puccinia graminis f. sp. tritici ( Pgt ) remains the major disease threat to wheat production. The Sr33 and Sr50 resistance proteins protect wheat against a broad spectrum of field isolates of Pgt and are closely related to the barley powdery mildew-resistance protein MLA10. Like MLA10, Sr33 and Sr50 poss...

Global wheat production is constrained by rust diseases and deployment of combinations of genetically diverse sources of resistance in new cultivars is accepted as a preferred means of rust control. This investigation was planned to identify new genomic regions contributing towards resistance to three rust diseases under field conditions in a W195/...

Wild relatives of domesticated crop species harbor multiple, diverse, disease resistance (R) genes that could be used to engineer sustainable disease control. However, breeding R genes into crop lines often requires long breeding timelines of 5–15 years to break linkage between R genes and deleterious alleles (linkage drag). Further, when R genes a...

Three rust pathogen species are present wherever wheat is grown and play a significant role in limiting wheat production. Multiple rust resistance gene combinations are considered as a practical solution for providing durable rust resistance and preventing resistance breakdown arising from single gene deployment. In recent years considerable effort...

We identify the wheat stem rust resistance gene Sr50 (using physical mapping, mutation and complementation) as homologous to barley Mla, encoding a coiled-coil nucleotide-binding leucine-rich repeat (CC-NB-LRR) protein. We show that Sr50 confers a unique resistance specificity different from Sr31 and other genes on rye chromosome 1RS, and is effect...

A major driver in Aegilops tauschii introgressions comes from the observation that the diploid D genome progenitor possesses a higher genetic diversity compared to their corresponding genomes in bread wheat cultivars and landraces. Since the mid-twentieth century directed efforts at Ae tauschii introgressions into wheat has come from two avenues. F...

As there are numerous pathogen species that cause disease and limit yields of crops, such as wheat (Triticum aestivum), single genes that provide resistance to multiple pathogens are valuable in crop improvement. The mechanistic basis of multi-pathogen resistance is largely unknown. Here we use comparative genomics, mutagenesis and transformation t...

Disease resistance is a critical goal for many wheat (Triticum aestivum L.) improvement programs. Wheat cultivars are affected by multiple diseases including the rusts and powdery mildew. The F6 recombinant inbred lines (RILs) derived from ‘Thatcher’∗3/‘CI13227’ that had been previously characterized as having adult‐plant leaf rust resistance gene...

The wheat gene Lr34 confers durable and partial field resistance against the obligate biotrophic, pathogenic rust fungi and powdery mildew in adult wheat plants. The resistant Lr34 allele evolved after wheat domestication through two gain-of-function mutations in an ATP-binding cassette transporter gene. An Lr34-like fungal disease resistance with...

Race Ug99 (TTKSK) of Puccinia graminis f. sp. tritici, detected in Uganda in 1998, has been recognized as a serious threat to food security because it possesses combined virulence to a large number of resistance genes found in current widely grown wheat (Triticum aestivum) varieties and germplasm, leading to its potential for rapid spread and evolu...

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

On Dec 4, 2015 this sequence version replaced gi:942473030. ##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

##Assembly-Data-START## Sequencing Technology :: Sanger dideoxy sequencing ##Assembly-Data-END##

Key message: A locus of major effect for stem rust resistance, effective against Ug99 and possibly a target of a suppressor on chromosome arm 7DL in wheat cultivar Canthatch, was mapped to 7AL. Wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is responsible for major production losses around the world. The development of resistan...

Stripe rust, caused by Puccinia striiformis f. sp. tritici W., is a devastating disease of wheat worldwide. A new stripe rust resistance gene with moderate seedling and adult plant resistance was mapped using an F5 recombinant inbred line (RIL) population developed from the cross of the resistant parent ‘Almop’ with the susceptible parent ‘Avocet’....

The spring wheat 'Canthatch' has been shown to suppress stem rust resistance genes in the background due to the presence of a suppressor gene located on the long arm of chromosome 7D. However, it is unclear whether the suppressor also suppresses resistance genes against leaf rust and stripe rust. In this study, we investigated the specificity of th...

Two new co-located resistance loci, QLr.cim - 1AS/QYr.cim - 1AS and QLr.cim - 7BL/YrSuj , in combination with Lr46 / Yr29 and Lr67/Yr46 , and a new leaf rust resistance quantitative trait loci, conferred high resistance to rusts in adult plant stage. The tall Indian bread wheat cultivar Sujata displays high and low infection types to leaf rust and...

The opinions expressed and arguments employed in this publication are the sole responsibility of the authors and do not necessarily refl ect those of the OECD or of the governments of its Member countries. The Special Session was sponsored by the OECD Cooperative Research Programme on Biological Resource Management for Sustainable Agricultural Syst...

Key message: Mapping studies confirm that resistance to Ug99 race of stem rust pathogen in Aegilops tauschii accession Clae 25 is conditioned by Sr46 and markers linked to the gene were developed for marker-assisted selection. The race TTKSK (Ug99) of Puccinia graminis f. sp. tritici, the causal pathogen for wheat stem rust, is considered as a maj...

The recently characterised and mapped adult plant resistance gene Lr67 contributes to the breeding of durable resistance against multiple fungal pathogens of wheat. Lack of tightly linked markers has so far prevented widespread use of Lr67 in breeding programmes. Exhaustive screening of available SSR markers and 9,000 gene-associated SNPs using bul...

Two classes of genes are used for breeding rust resistant wheat. The first class, called R (for resistance) genes, are pathogen race specific in their action, effective at all plant growth stages and probably mostly encode immune receptors of the nucleotide binding leucine rich repeat (NB-LRR) class. The second class is called adult plant resistanc...